sata_nv: cleanup CPB and APRD initialization

Clean up the initialization of the CPB and APRD structures so that we strictly follow the rules for ordering of writes to the CPB flags and response flags, and prevent duplicate initialization.

@@ -1164,11 +1159,7 @@ static void nv_adma_fill_aprd(struct ata

int idx,
struct nv_adma_prd *aprd)
{
- u8 flags;
-
- memset(aprd, 0, sizeof(struct nv_adma_prd));
-
- flags = 0;

+	u8 flags = 0;
	if (qc->tf.flags & ATA_TFLAG_WRITE)
		flags |= NV_APRD_WRITE;
	if (idx == qc->n_elem - 1)
@@ -1179,6 +1170,7 @@ static void nv_adma_fill_aprd(struct ata
	aprd->addr  = cpu_to_le64(((u64)sg_dma_address(sg)));
	aprd->len   = cpu_to_le32(((u32)sg_dma_len(sg))); /* len in bytes */
	aprd->flags = flags;

+ aprd->packet_len = 0;
}

static void nv_adma_fill_sg(struct ata_queued_cmd *qc, struct nv_adma_cpb *cpb) @@ -1199,6 +1191,8 @@ static void nv_adma_fill_sg(struct ata_q

	}
	if (idx > 5)
		cpb->next_aprd = cpu_to_le64(((u64)(pp->aprd_dma + NV_ADMA_SGTBL_SZ * qc->tag)));

+ else
+ cpb->next_aprd = cpu_to_le64(0);
}

static int nv_adma_use_reg_mode(struct ata_queued_cmd *qc) @@ -1231,7 +1225,10 @@ static void nv_adma_qc_prep(struct ata_q

		return;
	}

- memset(cpb, 0, sizeof(struct nv_adma_cpb));
+ cpb->resp_flags = NV_CPB_RESP_DONE;
+ wmb();
+ cpb->ctl_flags = 0;
+ wmb();

	cpb->len		= 3;
	cpb->tag		= qc->tag;
@@ -1255,6 +1252,8 @@ static void nv_adma_qc_prep(struct ata_q
	   finished filling in all of the contents */
	wmb();
	cpb->ctl_flags = ctl_flags;

+ wmb();
+ cpb->resp_flags = 0;
}

static unsigned int nv_adma_qc_issue(struct ata_queued_cmd *qc)